Work

Development of temperature-responsive dynamic-emissivity phase change material for all-season building energy savings

Year: 2025

Type: article

Abstract: Phase change material (PCM) applied on building envelope (e.g., roof, wall) has been proved to be effective for reducing both cooling and heating energy use. However, the infrared properties of conventional PCM are not properly considered, which would largely restrict the associate energy performance in practice. Recently, although preliminary studies have applied high-emissivity radiative cooling film/coating on PCM for enhancing cooling performance, the associate emissivity is static and thus it would result in poor heating performance at cold ambient. To this end, this study develops a dynamic-emissivity phase change material that integrates a temperature-responsive Fabry-Perot resonator with PCM using a facile and cost-effective method. The composite material can automatically achieve low emissivity for heating at hot ambient and high emissivity for cooling at cold ambient in response to temperature change, which matches the latent heat absorption and release of PCM for improving energy performance. Outdoor experiments show that the composite PCM can reduce and increase the indoor temperature by more than 3.5 °C at hot ambient and 1.5 °C at cold ambient, respectively in comparison with conventional PCM. Numerical simulations demonstrate the developed material can achieve 10.47% - 23.53% year-round energy savings across the diverse climate regions of China. At last, the color design of the composite is also conducted to cater for users' preference. This work paves new way to develop advanced PCM for all-season building energy savings.

Source: Applied Thermal Engineering

DOI: 10.1016/j.applthermaleng.2025.128655